A lasting deformation of keratin fibers is usually carried out in such a way that the fiber is deformed mechanically and the deformation is fixed by suitable aids. Before and/or after this deformation, the fibers are treated with a keratin-reducing preparation. After a rinsing operation, the fiber is then treated with an oxidizing agent preparation in the so-called fixing step, rinsed, and freed of the deformation aids (for example rollers, papillotes) after or during the fixing step. If a mercaptan, for example ammonium thioglycolate, is used as the keratin-reducing component, this cleaves some of the disulfide bridges of the keratin molecule to —SH groups, resulting in softening of the keratin fibers. During the subsequent oxidative fixing, disulfide bridges in the hair keratin are joined again so that the keratin structure is fixed in the predefined shape. Alternatively, instead of mercaptan, it is known to use sulfite for deforming hair. By means of hydrogen sulfite solutions and/or sulfite solutions and/or disulfite solutions, disulfide bridges of the keratin are cleaved in a sulfitolysis according to the equationR—S—S—R+HSO3(·)→R—SH+R—S—SO3(·)and in this way the keratin fibers are softened. Reducing agents including hydrogen sulfite, sulfite or disulfite do not have the strong odor of the agents containing mercaptan. The cleavage can be reversed, as outlined above, in a fixing step by means of an oxidizing agent to form new disulfide bridges.
The permanent straightening of keratin fibers is achieved in an analogous manner by using keratin-reducing and keratin-oxidizing compositions. In such a method, the curly hair is either wound onto rollers having a large diameter of usually more than 15 mm or the hair is combed straight under the effect of the keratin-reducing composition. Instead of the roller, it is also possible to lay the fibers straight on a straightening board. Straightening boards are usually rectangular sheets, for example made of plastic. Preferably, the fiber is wetted with the keratin-reducing preparation during this process.
A further possibility for straightening hair is straightening using hot irons. However, the structure of the keratin fiber changes during the heat treatment of the hair during the straightening operation. This change in the structure of the fiber should be counteracted by suitable measures.
Straightening by means of straightening irons can be aided by applying alkaline products beforehand. In contrast to styling by means of keratin-reducing and keratin-oxidizing compositions, such alkaline styling agents do not lead to a restructuring of the disulfide bridges but rather to a destruction of the disulfide bridges so as to form monosulfide bridges. Depending on the concentration and duration of application of the alkaline styling agents, protein chains are also hydrolytically cleaved. The pH of the alkaline styling agents is usually in the range of 11-14, preferably 12-13.
In general, the known styling methods, particularly in the case of straightening, have the disadvantage that the keratin fibers become electrostatically charged. In addition, the treatment with styling agents leads to an increased hydrophilicity of the hair, which makes it more difficult to manage and has a disadvantageous effect on hold, combability and shine.
The object of the invention is therefore to provide a styling method for keratin fibers, in particular for human hair, which delivers a very good and long-lasting styling result and at the same time minimizes the electrostatic charging and hydrophilization of the hair, cares for the fiber and is gentle on the structure of the fiber.
It has surprisingly been found that a treatment of the fibers with special styling agents prior to the styling process considerably minimizes the negative consequences of the styling and in particular minimizes the electrostatic charging and hydrophilization of the hair.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with this background of the invention.